October 2014

Journal

Effect of pressure on f-electron delocalization and oxidation in actinide dioxides

By:
Petit, Leon; Szotek, Zdzislawa; Temmerman, Walter; Stocks, George M; Svane, Axel
Journal Name:
Journal of Nuclear Materials
Page Number:
313-319
Volume:
451
Issue Number:
1-3
Publication Date:
October 2014
View DOI Listing:
https://doi.org/10.1016/j.jnucmat.2014.03.057

Abstract

Usingfirstprinciplescalculations,wehaveinvestigatedf-electrondelocalizationandoxidationintheactinidedioxidesunderpressure.WhilstUO2isfoundonthevergeofaninsulatortometaltransitionattheequilibriumvolume,increasinglylargerpressuresarerequiredtodelocalizef-electronsinNpO2,PuO2,andAmO2,respectively49,112,and191GPa.Comparedtothisbroadrangeofpressures,theexper-imentallyobservedstructuraltransitions,inallfourdioxides,occurbetween30and40GPa,whichleadsustoconcludethattheassociatedvolumecollapseisnotduetof-electrondelocalization.Incontrast,oxi-dationofthedioxidesisfoundtobelinkedtothedegreeoff-electronlocalization,butitemergesthatfornaturallyoccurringpressures(<10GPa),higheroxidesonlyexistforUO2.